Why aren’t more homes built out of cinder blocks since they’re cheap and stronger than wood?

On the surface that sounds reasonable, but the answer requires more.

As several others have mentioned cinder blocks are different from CMU (concrete masonry units) but still the price is similar. A block may cost about $1.00 ea while wood studs are $2–3 ea. You need one stud every 16″ plus bottom plate, double top plate plus sheathing, let’s call it $30 per 16″ section. Block takes 12 blocks to get to the same height so $12 per 16″ section.

Block wins let’s all go home. But, wait!

Studs require nails, screws, and hardware. Block walls require rebar, anchor hardware, and grout. And studs require less than half the labor that block does. Also, block buildings require much sturdier floors and roofs as block walls can exert much greater forces on those elements.

In general, wood framed structures tend to be the easiest and cheapest to construct. We usually only consider things like block construction when there is an increased concern about fire and egress.

Typically, a structure that is constructed out of block and is cheaper than wood frame is a dangerously under constructed structure.